Question
What is the origin of the Forty Hours devotions?
--Focused in Phoenix
Answer
The practices comes from the late medieval period when eucharistic devotions, connected with the Sacred Triduum began. After the Holy Thursday evening procession with the Blessed Sacrament, people took turns praying in front of the altar where the sacrament was reserved until Holy Saturday. This was a period of forty hours. According to Saint Augustine in his work, "On the Trinity," Jesus would have lain in the tomb for a period of forty hours.
Later on in history, the forty hours were kept for other solemnities, such as Christmas, Ascension and Pentecost. As the practice spread, other churches would have preachers come and give "mission" talks with a penitential nature. The devotion quickly spread throughout Europe. In modern times, there has been less of an aspect of penance and reparation for sin and a more prolonged period of exposition of the Blessed Sacrament. "Forty hours" is also some times referred to as "a parish mission" which may or may not be centered on eucharistic devotion..